syzbot


possible deadlock in proc_pid_syscall

Status: upstream: reported syz repro on 2020/06/24 12:57
Reported-by: syzbot+e96aae4bf7ce37e2eaef@syzkaller.appspotmail.com
First crash: 1345d, last: 430d
Fix bisection: failed (error log, bisect log)
  
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in proc_pid_syscall (2) fs 2 1270d 1280d 19/26 fixed on 2021/03/10 01:48
upstream possible deadlock in proc_pid_syscall fs 11 1428d 1566d 0/26 auto-closed as invalid on 2020/07/31 06:50
linux-4.14 possible deadlock in proc_pid_syscall C error 19 535d 1299d 0/1 upstream: reported C repro on 2020/08/09 14:10

Sample crash report:
IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready
IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
======================================================
WARNING: possible circular locking dependency detected
wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
4.19.191-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/9562 is trying to acquire lock:
000000003f26e7b9 (&sig->cred_guard_mutex){+.+.}, at: lock_trace fs/proc/base.c:402 [inline]
000000003f26e7b9 (&sig->cred_guard_mutex){+.+.}, at: proc_pid_syscall+0xb8/0x2f0 fs/proc/base.c:635

but task is already holding lock:
00000000da084160 (&p->lock){+.+.}, at: seq_read+0x6b/0x1160 fs/seq_file.c:161

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&p->lock){+.+.}:
IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready
       seq_read+0x6b/0x1160 fs/seq_file.c:161
       do_loop_readv_writev fs/read_write.c:701 [inline]
       do_loop_readv_writev fs/read_write.c:688 [inline]
       do_iter_read+0x471/0x630 fs/read_write.c:925
       vfs_readv+0xe5/0x150 fs/read_write.c:987
wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
       kernel_readv fs/splice.c:362 [inline]
       default_file_splice_read+0x457/0xa00 fs/splice.c:417
       do_splice_to+0x10e/0x160 fs/splice.c:881
       splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
       do_splice_direct+0x1a7/0x270 fs/splice.c:1068
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
       do_sendfile+0x550/0xc30 fs/read_write.c:1447
IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready
       __do_sys_sendfile64 fs/read_write.c:1508 [inline]
       __se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494
       do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #2 (sb_writers#3){.+.+}:
       sb_start_write include/linux/fs.h:1579 [inline]
       mnt_want_write+0x3a/0xb0 fs/namespace.c:360
       ovl_create_object+0x96/0x290 fs/overlayfs/dir.c:600
IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready
       lookup_open+0x893/0x1a20 fs/namei.c:3235
       do_last fs/namei.c:3327 [inline]
       path_openat+0x1094/0x2df0 fs/namei.c:3537
       do_filp_open+0x18c/0x3f0 fs/namei.c:3567
ieee80211 phy10: Selected rate control algorithm 'minstrel_ht'
       do_sys_open+0x3b3/0x520 fs/open.c:1085
       do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
       entry_SYSCALL_64_after_hwframe+0x49/0xbe
IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready

-> #1 (&ovl_i_mutex_dir_key[depth]){++++}:
       inode_lock_shared include/linux/fs.h:758 [inline]
       do_last fs/namei.c:3326 [inline]
       path_openat+0x17ec/0x2df0 fs/namei.c:3537
       do_filp_open+0x18c/0x3f0 fs/namei.c:3567
       do_open_execat+0x11d/0x5b0 fs/exec.c:853
wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
       __do_execve_file+0x1a8b/0x2360 fs/exec.c:1770
       do_execveat_common fs/exec.c:1879 [inline]
       do_execve+0x35/0x50 fs/exec.c:1896
       __do_sys_execve fs/exec.c:1977 [inline]
       __se_sys_execve fs/exec.c:1972 [inline]
       __x64_sys_execve+0x7c/0xa0 fs/exec.c:1972
       do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
       entry_SYSCALL_64_after_hwframe+0x49/0xbe
wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50

-> #0 (&sig->cred_guard_mutex){+.+.}:
       __mutex_lock_common kernel/locking/mutex.c:928 [inline]
       __mutex_lock+0xd7/0x1260 kernel/locking/mutex.c:1075
       lock_trace fs/proc/base.c:402 [inline]
       proc_pid_syscall+0xb8/0x2f0 fs/proc/base.c:635
       proc_single_show+0xeb/0x170 fs/proc/base.c:755
       seq_read+0x4be/0x1160 fs/seq_file.c:229
ieee80211 phy11: Selected rate control algorithm 'minstrel_ht'
       do_loop_readv_writev fs/read_write.c:701 [inline]
       do_loop_readv_writev fs/read_write.c:688 [inline]
       do_iter_read+0x471/0x630 fs/read_write.c:925
       vfs_readv+0xe5/0x150 fs/read_write.c:987
       kernel_readv fs/splice.c:362 [inline]
       default_file_splice_read+0x457/0xa00 fs/splice.c:417
       do_splice_to+0x10e/0x160 fs/splice.c:881
       splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
       do_splice_direct+0x1a7/0x270 fs/splice.c:1068
       do_sendfile+0x550/0xc30 fs/read_write.c:1447
       __do_sys_sendfile64 fs/read_write.c:1508 [inline]
       __se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494
       do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

Chain exists of:
  &sig->cred_guard_mutex --> sb_writers#3 --> &p->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&p->lock);
                               lock(sb_writers#3);
                               lock(&p->lock);
  lock(&sig->cred_guard_mutex);

 *** DEADLOCK ***

2 locks held by syz-executor.2/9562:
 #0: 0000000025209a34 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline]
 #0: 0000000025209a34 (sb_writers#3){.+.+}, at: do_sendfile+0x97d/0xc30 fs/read_write.c:1446
 #1: 00000000da084160 (&p->lock){+.+.}, at: seq_read+0x6b/0x1160 fs/seq_file.c:161

stack backtrace:
CPU: 0 PID: 9562 Comm: syz-executor.2 Not tainted 4.19.191-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222
 check_prev_add kernel/locking/lockdep.c:1866 [inline]
 check_prevs_add kernel/locking/lockdep.c:1979 [inline]
 validate_chain kernel/locking/lockdep.c:2420 [inline]
 __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416
 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
 __mutex_lock_common kernel/locking/mutex.c:928 [inline]
 __mutex_lock+0xd7/0x1260 kernel/locking/mutex.c:1075
 lock_trace fs/proc/base.c:402 [inline]
 proc_pid_syscall+0xb8/0x2f0 fs/proc/base.c:635
 proc_single_show+0xeb/0x170 fs/proc/base.c:755
 seq_read+0x4be/0x1160 fs/seq_file.c:229
 do_loop_readv_writev fs/read_write.c:701 [inline]
 do_loop_readv_writev fs/read_write.c:688 [inline]
 do_iter_read+0x471/0x630 fs/read_write.c:925
 vfs_readv+0xe5/0x150 fs/read_write.c:987
IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready
wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
 kernel_readv fs/splice.c:362 [inline]
 default_file_splice_read+0x457/0xa00 fs/splice.c:417
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
ieee80211 phy12: Selected rate control algorithm 'minstrel_ht'
IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready
IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
 do_splice_to+0x10e/0x160 fs/splice.c:881
 splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959
wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
ieee80211 phy13: Selected rate control algorithm 'minstrel_ht'
 do_splice_direct+0x1a7/0x270 fs/splice.c:1068
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready
 do_sendfile+0x550/0xc30 fs/read_write.c:1447
 __do_sys_sendfile64 fs/read_write.c:1508 [inline]
 __se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494
wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready
RIP: 0033:0x4665d9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6087737188 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
overlayfs: './bus' not a directory
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665d9
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000004
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000007 R11: 0000000000000246 R12: 000000000056c038
R13: 00007ffd2d4933bf R14: 00007f6087737300 R15: 0000000000022000
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
audit: type=1800 audit(1621882336.927:2): pid=9691 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed comm="syz-executor.5" name="bus" dev="overlay" ino=13931 res=0
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
audit: type=1800 audit(1621882337.007:3): pid=9700 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed comm="syz-executor.4" name="bus" dev="overlay" ino=13947 res=0
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
audit: type=1800 audit(1621882337.698:4): pid=9845 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed comm="syz-executor.3" name="bus" dev="overlay" ino=13908 res=0
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory
overlayfs: './bus' not a directory

Crashes (161):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/05/24 19:07 linux-4.19.y 1e986fe9ad15 3c7fef33 .config console log report syz ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/12/26 00:55 linux-4.19.y 3f8a27f9e27b 9da18ae8 .config console log report info [disk image] [vmlinux] ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/11/15 08:00 linux-4.19.y 3f8a27f9e27b 97de9cfc .config console log report info [disk image] [vmlinux] ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/10/30 09:53 linux-4.19.y 3f8a27f9e27b 2a71366b .config console log report info [disk image] [vmlinux] ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/10/20 21:43 linux-4.19.y 3f8a27f9e27b a0fd4dab .config console log report info [disk image] [vmlinux] ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/10/01 15:36 linux-4.19.y 3f8a27f9e27b feb56351 .config console log report info [disk image] [vmlinux] ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/09/19 21:24 linux-4.19.y 3f8a27f9e27b dd9a85ff .config console log report info [disk image] [vmlinux] ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/09/05 00:52 linux-4.19.y 3f8a27f9e27b 28811d0a .config console log report info [disk image] [vmlinux] ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/09/04 17:18 linux-4.19.y 3f8a27f9e27b 28811d0a .config console log report info [disk image] [vmlinux] ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/09/04 05:34 linux-4.19.y 3f8a27f9e27b 28811d0a .config console log report info [disk image] [vmlinux] ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/08/15 13:20 linux-4.19.y 3f8a27f9e27b 8dfcaa3d .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/08/04 03:23 linux-4.19.y 3f8a27f9e27b 1c9013ac .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/07/20 12:17 linux-4.19.y 3f8a27f9e27b 775344bc .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/07/12 02:43 linux-4.19.y 3f8a27f9e27b da3d6955 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/07/10 12:35 linux-4.19.y 3f8a27f9e27b b5765a15 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/07/02 00:04 linux-4.19.y 3f8a27f9e27b 1434eec0 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/06/21 16:44 linux-4.19.y 3f8a27f9e27b 0fc5c330 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/06/18 10:05 linux-4.19.y 3f8a27f9e27b 8f633d84 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/06/16 14:22 linux-4.19.y 3f8a27f9e27b 1719ee24 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/06/03 16:54 linux-4.19.y 3f8a27f9e27b eee80d3c .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/06/01 19:54 linux-4.19.y 3f8a27f9e27b b4bc6a3d .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/05/30 16:19 linux-4.19.y 3f8a27f9e27b af70c3a9 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/05/23 02:21 linux-4.19.y 3f8a27f9e27b 7268fa62 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/05/16 02:06 linux-4.19.y 3f8a27f9e27b 744a39e2 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/05/02 01:53 linux-4.19.y 3f8a27f9e27b 2df221f6 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/04/26 21:55 linux-4.19.y 3f8a27f9e27b 1fa34c1b .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/04/16 12:37 linux-4.19.y 3f8a27f9e27b 8bcc32a6 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/04/11 21:48 linux-4.19.y 3f8a27f9e27b af01ee7d .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/03/12 01:59 linux-4.19.y 3f8a27f9e27b 9e8eaa75 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/03/06 02:16 linux-4.19.y 3f8a27f9e27b 7bdd8b2c .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/03/03 22:06 linux-4.19.y 3f8a27f9e27b 45a13a73 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/02/17 10:07 linux-4.19.y 3f8a27f9e27b 2bea8a27 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/02/16 20:48 linux-4.19.y 3f8a27f9e27b 50221962 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/02/15 11:57 linux-4.19.y 3f8a27f9e27b 8b9ca619 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/02/10 17:04 linux-4.19.y 3f8a27f9e27b 0b33604d .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/02/08 01:26 linux-4.19.y 3f8a27f9e27b a7dab638 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/02/04 00:58 linux-4.19.y 3f8a27f9e27b 30646bfe .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/02/03 20:55 linux-4.19.y 3f8a27f9e27b 30646bfe .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/02/02 10:54 linux-4.19.y 3f8a27f9e27b 4ebb2798 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/02/02 07:41 linux-4.19.y 3f8a27f9e27b 4ebb2798 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/01/30 11:10 linux-4.19.y 3f8a27f9e27b 495e00c5 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/01/30 06:27 linux-4.19.y 3f8a27f9e27b 495e00c5 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2022/01/30 05:45 linux-4.19.y 3f8a27f9e27b 495e00c5 .config console log report info ci2-linux-4-19 possible deadlock in proc_pid_syscall
2020/11/26 14:56 linux-4.19.y 0c88e405c97e 2f1cec62 .config console log report info ci2-linux-4-19
2020/06/24 12:57 linux-4.19.y b3a99fd385fa 41694dbf .config console log report ci2-linux-4-19
* Struck through repros no longer work on HEAD.